1. Field of the Invention
The present application generally relates to a display panel and a driving method thereof. More particularly, the present application relates to a liquid crystal display (LCD) panel and a driving method thereof.
2. Description of Related Art
In order to meet the requirements of high speed, high efficiency, light weight, and compactness for modern products, electronic parts have been vigorously developed towards miniaturization. Various mobile electronic devices have become the mainstream, e.g. notebook computers, cell phones, electronic dictionaries, personal digital assistants (PDAs), web pads, tablet personal computers (PCs), and so forth. To satisfy demands for miniaturized image display panels of mobile electronic devices, LCD panels having superior characteristics, such as favorable space utilization, high resolution, low power consumption, and no radiation have been extensively applied nowadays.
In general, an LCD panel is mainly formed by a plurality of scan lines, a plurality of data lines, and a plurality of pixels respectively driven by corresponding scan lines and data lines. Recently, to popularize the LCD panels and to comply with an energy-saving trend, manufacturers are eager to reduce both the costs and power consumption. Accordingly, a method has been proposed to reduce the number of data driving chips through the layout of a pixel array.
FIG. 1A is a schematic view illustrating a conventional LCD panel with a tri-gate driving structure. As indicated in FIG. 1A, the LCD panel 100 has a plurality of pixel units U arranged in array. Each of the pixel units U includes sub-pixels PR, PG, and PB sequentially arranged along a column direction. The sub-pixels PR, PG, and PB are electrically connected to corresponding scan lines G and corresponding data lines D through corresponding active devices, respectively. In FIG. 1A, some of the sub-pixels in two columns of pixels P share the same data line D for transmitting corresponding data signals. Under said framework, the number of scan lines G increases, while the number of data lines D decreases. That is to say, the number of data driving chips 110 which are bonded to the LCD panel 100 can be reduced in an effective manner. Since the data driving chips require high manufacturing costs, and therefore the decrease in the number of data driving chips 110 is conducive to cost reduction. On the other hand, signals processed by the data driving chips 110 are rather complicated and power-consuming, and therefore power consumed by the LCD panel 100 can be saved to a better degree when less data driving chips 110 are used.
Nonetheless, with the product demands for high resolution, turn-on time of each scan line is reduced. When an image of alternate black and white patterns, such as images of “11111111” or “dddddddd”, is displayed on the LCD panel. Thereby, response time of a common voltage Vcom corresponding to the sub-pixels in each row is insufficient, which leads to a crosstalk effect in the neighboring sub-pixels and mura phenomenon on the LCD panel.
FIG. 1B is a schematic view illustrating the LCD panel depicted in FIG. 1A in a driving state and in a display state. As indicated in FIGS. 1A and 1B, through applying a dot-inversion driving method, the sub-pixels PR, PG, and PB in the LCD panel are driven to display an image of alternate black and white patterns. Since the active devices electrically connected to the same data line are alternately arranged at two sides of the data line along the column direction, the sub-pixels into which data signals are written through the same data line are arranged in a zigzag pattern. In FIG. 1B, an exemplary signal with a negative polarity is transmitted through the data line D(4) and input into the sub-pixels in two columns C3 and C4. The sub-pixels of the two columns C3 and C4 electrically connected to the data line D(4) and alternately arranged at two sides of the data line D(4) show a negative polarity.
FIG. 1C is a schematic view illustrating waveforms of driving some of the data lines depicted in FIG. 1B. In FIG. 1C, the LCD panel displaying normally white images is taken for example. As shown in FIGS. 1B and 1C, signals transmitted through the data lines D(4) and D(5) have a negative polarity and a positive polarity, respectively. Besides, according to time sequence, data voltages in an order of black, white, black, white, and black are respectively input into the sub-pixels in rows R1, R2, R3, R4, and R5 through the data line D(4) used for transmitting the signals with the negative polarity; data voltages in an order of white, black, white, black, and white are input into the sub-pixels in the rows R1, R2, R3, R4, and R5 through the data line D(5) used for transmitting the signals with the positive polarity.
With reference to FIG. 1C, in general, the common electrode is coupled by the data lines, and the voltage of the common electrode is varied by a coupling effect arisen from a variation in data polarity with time sequence. Due to the fact that the voltage coupling effect arisen from different polarity signals transmitted in the data line D(4) with time sequence is the same as the voltage coupling effect arisen from the data lines D(5) with the same time sequence, the total coupling of the common electrode cannot be eliminated. Thereby, the common voltage Vcom is shifted.
FIG. 1D is a schematic view illustrating mura phenomenon occurring in a conventional LCD panel. With reference to FIG. 1D, alternate black and white patterns are usually displayed on the LCD panel by the sub-pixels in a plurality of rows. Therefore, when the alternate black and white patterns are displayed on the LCD panel by the sub-pixels (as shown in the upper part of FIG. 1D), said common voltage shift likely results in mura phenomenon at two sides of the sub-pixels (as shown in the lower part of FIG. 1D). Particularly, when gray or monochrome patterns serve as backgrounds, the mura phenomenon becomes more conspicuous.